Fix concurrency issues

Fixes ArrayIndexOutOfBoundsException that can occur when serializing dates concurrently.
Also cache the value of "UTC" TimeZone locally to avoid contention to synchronized
`getTimeZone` method.

Fixes guyboertje#76, guyboertje#77

Rakefile

@@ -10,7 +10,7 @@ end
 
 desc "Run benchmarks"
 task :benchmark do
-  load 'benchmarking/benchmark.rb'
+  load 'benchmarking/benchmark_threaded.rb'
 end
 
 desc "Pack jar after compiling classes, use this to rebuild the pom.xml"

benchmarking/benchmark_threaded.rb

@@ -8,6 +8,7 @@
 require 'json/ext'
 require 'gson'
 
+require File.expand_path('lib/jrjackson_jars')
 require File.expand_path('lib/jrjackson')
 
 HASH = {:one => nil, :two => nil, :three => nil, :four => {:a => nil, :b => nil, :c =>nil},
@@ -24,6 +25,10 @@ def random_number
   rand 999_999_999
 end
 
+def random_date
+  Time.at(rand * Time.now.to_i)
+end
+
 def random_float
   random_number + rand
 end
@@ -36,40 +41,73 @@ def fill_array
   value
 end
 
-def randomize_entries hsh
+def randomize_entries hsh, include_dates
   new_hsh = {}
   hsh.each_pair do |key, value|
     case value
     when NilClass
-      new_hsh[key] = send METHODS[rand(3)]
+      new_hsh[key] = send METHODS[rand(include_dates ? 4 : 3)]
     when Hash
-      new_hsh[key] = randomize_entries value
+      new_hsh[key] = randomize_entries value, include_dates
     when Array
       new_hsh[key] = fill_array
     end
   end
   new_hsh
 end
 
-METHODS = [:random_string, :random_number, :random_float]
+METHODS = [:random_string, :random_number, :random_float, :random_date]
 
 org_array = []
+no_dates_array = []
 one = []
 
 0.upto(5000) do |i|
   hsh = HASH.dup
-  org_array << randomize_entries(hsh)
+  org_array << randomize_entries(hsh, true)
+end
+
+0.upto(5000) do |i|
+  hsh = HASH.dup
+  no_dates_array << randomize_entries(hsh, false)
 end
 
+
 generated_array = []
 generated_smile = []
 
 org_array.each do |hsh|
-  generated_array << JrJackson::Raw.generate(hsh)
+  generated_array << JrJackson::Base.generate(hsh)
 end
 
 q = Queue.new
 
+
+Benchmark.bmbm("Jackson generate with no dates".size) do |x|
+  x.report("Jackson generate with dates") do
+    threads = 100.times.map do
+      Thread.new do
+        org_array.each do |hsh|
+          JrJackson::Base.generate(hsh)
+        end
+      end
+    end
+    threads.each(&:join)
+  end
+
+  x.report("Jackson generate with no dates") do
+
+    threads = 100.times.map do
+      Thread.new do
+        no_dates_array.each do |hsh|
+          JrJackson::Base.generate(hsh)
+        end
+      end
+    end
+    threads.each(&:join)
+  end
+end
+
 Benchmark.bmbm("jackson parse symbol keys:  ".size) do |x|
 
   x.report("json java parse:") do

changelog.md

@@ -1,3 +1,7 @@
+v0.4.10
+  fix concurrency issue when serializing dates. Also cache the value of "UTC" TimeZone locally to 
+  avoid contention to synchronized `getTimeZone` method.
+
 v0.4.9
   bump Jackson to v2.9.9, and jackson-databind to v2.9.9.3
 

lib/jrjackson/build_info.rb

@@ -1,11 +1,11 @@
 module JrJackson
   module BuildInfo
     def self.version
-      '0.4.9'
+      '0.4.10'
     end
 
     def self.release_date
-      '2019-08-09'
+      '2019-09-24'
     end
 
     def self.files

src/main/java/com/jrjackson/RubyAnySerializer.java

@@ -237,11 +237,11 @@ private void serializeTime(RubyTime dt, JsonGenerator jgen, SerializerProvider p
         } else if (df instanceof RubyDateFormat) {
             // why another branch? I thought there was an easy win on to_s
             // maybe with jruby 9000
-            RubyDateFormat rdf = (RubyDateFormat) df.clone();
-            jgen.writeString(rdf.format(dt.getJavaDate()));
+            RubyDateFormat clonedRubyDatFormat = (RubyDateFormat) df.clone();
+            jgen.writeString(clonedRubyDatFormat.format(dt.getJavaDate()));
         } else {
-            SimpleDateFormat sdf = (SimpleDateFormat) df.clone();
-            jgen.writeString(df.format(dt.getJavaDate()));
+            SimpleDateFormat clonedSimpleDateFormat = (SimpleDateFormat) df.clone();
+            jgen.writeString(clonedSimpleDateFormat.format(dt.getJavaDate()));
         }
     }
 

src/main/java/com/jrjackson/RubyJacksonModule.java

@@ -17,6 +17,7 @@
 public class RubyJacksonModule extends SimpleModule {
     public static final ObjectMapper static_mapper = new ObjectMapper();
     public static final JsonFactory factory = new JsonFactory(static_mapper).disable(JsonFactory.Feature.FAIL_ON_SYMBOL_HASH_OVERFLOW);
+    private static final TimeZone utcTimeZone = TimeZone.getTimeZone("UTC");
 
     static {
         static_mapper.registerModule(new RubyJacksonModule().addSerializer(
@@ -55,7 +56,7 @@ public static DefaultSerializerProvider createProvider(SimpleDateFormat sdf) {
 
     public static DefaultSerializerProvider createProvider() {
         SimpleDateFormat rdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z");
-        rdf.setTimeZone(TimeZone.getTimeZone("UTC"));
+        rdf.setTimeZone(utcTimeZone);
         return createProvider(rdf);
     }
 

test/jrjackson_test.rb

@@ -548,6 +548,21 @@ def test_can_handle_big_numbers
     assert_equal "{\"foo\":9223372036854775808,\"bar\":65536}", actual
   end
 
+
+  # This test failed more often than not before fixing the underlying code
+  # and would fail every time if `100_000.times` was changed to `loop`
+  def test_concurrent_dump
+    now = Time.now
+    num_threads = 100
+
+    threads = num_threads.times.map do |i|
+      Thread.new do
+        100_000.times { JrJackson::Json.dump("a" => now) }
+      end
+    end
+    threads.each(&:join)
+  end
+
   # -----------------------------
 
   def assert_bigdecimal_equal(expected, actual)